Doctor Who: 10 Most Powerful Daleks Ever

Leader of the Cult of Skaro - an elite group created by the Dalek Emperor during the Time War to devise new ways of killing - this black Dalek was ruthless, dedicated to his mission, and uniquely creative.

Considered to be the most intelligent of the Dalek race by the Tenth Doctor, Sec had been instructed to think like the enemy. Becoming a cunning strategist, this black Dalek had great plans for his species. Being more creative and independent of Dalek beliefs, Sec and his Cult of Skaro brethren even had names - unheard of in Dalek society.

First appearing in 2006's Army of Ghosts/Doomsday, Sec was the first new series Dalek to hold a leadership rank and have an altered colour scheme from the usual bronze Daleks. Memorably battling the Cybermen at Canary Wharf and briefly releasing millions of Daleks from the Genesis Ark, his mission was to allow the Dalek race to survive - by any means possible.

Escaping to 1930s New York, Sec achieved what no other Dalek could, or would, imagine. He released himself from his shell and merged with a human to become the first Dalek-Human Hybrid.

With his intelligence mingling with the emotions and humanity of his new host, Sec began to rethink his mission of extermination and domination. The rest of the Cult of Skaro, however, didn't agree with him and he was exterminated.

Dalek Sec was one of the most unusual and unique Daleks to ever appear in Doctor Who. Having been described as being 'above and beyond the emperor', who knows where he actually ranked within the Dalek Empire.